1. Field of the Invention
The present invention relates to caches in computer systems. More specifically, the present invention relates to a method and apparatus which detects the presence of a cache and, if any is present, the characteristics of the cache.
2. Background Information
As part of the normal self-test routine of a computer system, the presence and validity of a cache contained within the system is normally performed. Cache memory in different computer systems varies widely from system to system. Different chipsets report different cache sizes differently. Prior art methods of determining cache size have been limited to programs specific to particular chipsets that query the chipset for the cache size information. That is , a different program needs to be written for each different chipset.
Cache size and characteristics have been set in many previous environments via the use of jumper settings or other hardware configurations on a computer system motherboard. If the hardware configuration does not correspond with the resources in the system, however, the cache size and type will be reported incorrectly.
Prior art techniques have also been lacking in determining specific characteristics of caches, such as multi-levels of caches. Techniques which can apply to any computer system are lacking which allow the determination of the set-associativity of a cache. Lastly, the prior art lacks a generalized method for determining whether data and instruction caches are unified.
Thus, one prior art need is a single methodology which would detect the presence and size of caches in a variety of computer system architectures with different chipsets. In addition to size and presence of a cache, type (e.g., instruction, data, or unified cache) and set associativity of caches as well may be required to be determined. Also, multiple levels of caches should be able to be determined using a single technique applicable across a wide variety of computer system chipsets and computer system architectures to avoid the deficiencies of the prior art.